The present disclosure relates to a power transmission belt.
As a means for transmitting the rotative power generated by an engine, a motor or any other drive sources for use in various types of machines, automobiles and other structures, a power transmission belt such as a frictional transmission belt is generally used. If such a transmission belt becomes wet with water pouring, then belt slipping and other unwanted phenomena will arise to a more significant degree, so-called “stick-slip” abnormal noise will be generated, and its power transmission performance will decline to cause deterioration in its fuel consumption.
To overcome such a problem, Japanese Unexamined Patent Publication No. 2004-176904 discloses a V-ribbed belt, of which a portion that contacts with a pulley is made of a rubber composition including porous acrylic short fibers. According to this document, the contact portion made of such a material allows the water poured to be absorbed and drained effectively enough to reduce the slipping.
The frictional transmission belt disclosed in Japanese Unexamined Patent Publication No. 2004-176904 is effective to a certain degree in reducing the generation of abnormal noise and a decline in power transmission performance at the time of water pouring. However, further improvements need to be achieved in order to meet growing demands for high-performance transmission belts. In view of the foregoing background, it is therefore an object of the present disclosure to provide a frictional transmission belt which may operate with reduced abnormal noise even in a more stressful environment (e.g., when the belt needs to be driven with a non-negligible degree of misalignment, or is supplied with a lot of water, or causes a significant variation with rotation).